Anti-virus agent and method for treatment of viral infection

ABSTRACT

A method of treatment of viral infection in a subject comprising administering to the subject a copolymer comprising an acrolein derived segment or a polyacrolein oligomer segment and a polyalkylene glycol oligomer segment, the copolymer having a molecular weight of no more than 1500 Daltons.

FIELD

The invention relates to a method of treatment of viral infection,particularly parenteral viral infection, using a copolymer comprising anacrolein-derived segment and a polyalkylene glycol oligomer segmentwherein the copolymer has a molecular weight of up to 1500 Daltons,preferably up to 1000 Daltons, and to a process for the preparation ofthe copolymer by polymerization of acrolein in an aqueous solution ofthe polyalkylene glycol.

BACKGROUND

Viruses having a lipid envelope or coat—usually hydrophobic, areimportant human and animal pathogens. Examples of conditions associatedwith such viruses include Orthomyxoviruses (influenza viruses), HIV,Hepatitis, Ross River and Herpes. The Herpes viruses cause both primaryand secondary infections that range from trivial mucosal ulcers to lifethreatening disorders in immuno-compromised patients. The Herpes groupincludes HSV-1, HSV-2, Herpes Zoster (chicken pox/shingles), HCMV (humancytomegalovirus), Epstein Barr Virus (EBV), Herpes 6, 7 (Roseola, posttransplant infections) and Herpes 8 (associated with Kaposi sarcoma).

Persons infected with a Herpes type virus are typically subjected tocycles of outbreaks where symptoms are experienced and asymptomaticlatent periods. During the latent periods, the virus resides in theganglia where it is inactive and the patient is asymptomatic. However,although asymptomatic, a patient may still be able to infect others.This is known as viral shedding. Reoccurrence of symptoms can occur whenthe virus is reactivated. Reactivation can be triggered by manydifferent events and is particularly problematic in immunocompromisedpatients.

There is a need in the art for alternative antiviral therapies. Thepresent invention in one set of embodiments addresses these needs andprovides for methods of treating viral infection.

Acrolein is extremely damaging to body tissues due to its highreactivity. Connections exist between acrolein gas in the smoke fromtobacco cigarettes and the risk of lung cancer (Feng, Z; Hu W; Hu Y;Tang M (October 2006). “Acrolein is a major cigarette-related lungcancer agent: Preferential binding at p53 mutational hotspots andinhibition of DNA repair”. Proceedings of the National Academy ofSciences 103 (42): 15404-15409). Pure polyacrolein, alone is not knownto exhibit significant antiviral activity. However, a number of patentsincluding U.S. Pat. No. 5,290,894, Melrose et al., disclose thepreparation and uses of modified polyacroleins as potential antiviralagents for treatment of viral infection via the gastrointestinal tract.Further examples of polyacrolein of this type are described in U.S. Pat.Nos. 6,723,336, 7,629,002 and 9,119,394. Acrolein is an extremelyreactive monomer and when polymerized, rapidly forms a high molecularweight intractable network. Normally, anionic polymerizations areconducted in a solvent free of water and provide rapid polymerizationsto form high molecular weight polymers.

One of the perceived advantages of the polymers described in the priorart is that they cannot penetrate the gut wall so that their activity isconfined to the gastrointestinal tract. U.S. Pat. No. 9,119,394(Melrose) describes a polyacrolein polymer which may be formed by basecatalyzed polymerization of acrolein and/or its acetal with an alkanol.The polymers have the advantage of a reduced propensity to migratethrough membranes, specifically the membrane of the gastrointestinaltract.

U.S. Pat. No. 6,060,571 (Werle et al.) describes acrolein releasingpolymers which release sufficient acrolein to provide activity assanitizing agents in water systems. Such polymers are not suitable foruse in vivo due to the toxicity of the significant levels of acroleinreleased in aqueous media.

The discussion of the background to the invention herein is included toexplain the context of the invention. This is not to be taken as anadmission that any of the material referred to was published, known orpart of the common general knowledge as at the priority date of any ofthe claims.

SUMMARY

We have now found that low molecular weight copolymers comprising anacrolein-derived segment and polyalkylene glycol oligomer segment may beprepared so as to limit the molecular weight of the copolymer to no morethan 1500 Daltons, preferably no more than 1000 Daltons. Further we havefound that the low molecular weight copolymers provide potent anti-virusactivity and may be used for treatment of parenteral viral infection,without release of acrolein monomer. Indeed the activity is enhancedwhen compared with acrolein polymers of higher molecular weight.

According to one set of embodiments, there is provided a method for thetreatment, control or prophylaxis of a viral infection in a subject, themethod including administering to the subject a copolymer comprising anacrolein-derived segment and a polyalkylene glycol oligomer segment(preferably of molecular weight of from 200 to 600 Daltons), thecopolymer having a molecular weight of no more than 1500 Daltons,preferably no more than 1000 Daltons.

According to a further set of embodiments there is provided a method oftreatment of viral infection (preferably a parenteral viral infection)in vivo comprising the step of contacting at least one target infectedcell in vivo with an effective amount of a copolymer comprising anacrolein-derived segment and a polyalkylene glycol oligomer segment, thecopolymer having a molecular weight of no more than 1500 Daltons,preferably no more than 1000 Daltons.

The viral infection may be caused by a range of viruses such as coatedviruses (e.g. lipid coated viruses) including herpes, HIV,cytomegalovirus and influenza. Preferably, the viral infection treatedand/or controlled by the method of the invention may be HSV-1, HSV-2,Vadcella Zoster Virus (in the form of chicken pox or shingles), HCMV,EBV, Herpes 6, Herpes 7 and Herpes 8.

In another embodiment the virus is influenza virus such as influenza A.

In yet a further embodiment the virus is Ross River virus.

The method of the invention may be particularly suitable for thetreatment of viral infections in an immunosuppressed individual. Themethod of the invention may also be used as an adjunct therapy withother anti-viral therapies.

In yet a further aspect there is provided a process for preparation of acopolymer comprising an acrolein-derived segment (such as a polyacroleinoligomer) and a polyalkylene glycol oligomer comprising copolymerizingacrolein and polyalkylene glycol oligomer under conditions of alkalinecatalysis of pH no more than 12.0 and within a pH range of 12.0 to 7.0in an aqueous solution comprising at least 20% w/w water, and thepolyalkylene glycol oligomer (preferably of molecular weight of from 200to 600 Daltons) in a weight ratio of polyalkylene glycol/acrolein of atleast 4, preferably at least 10.

Definitions

The term “body” means the body of humans and/or animals; the term“subject” means such a body which is the subject.

Intravenous therapy (IV therapy or iv therapy in short) is the infusionof liquid substances directly into a vein.

As used herein, the term “parenteral” means taken into the body in amanner other than through the intact digestive canal. That is, notwithin the normal stomach or intestine; not intestinal.

The term “parenteral viral infection” refers to a viral infectioncontracted in the body not within the gastro-intestinal tract.

The term “pulmonary administration” refers to administration of aformulation of the invention into the lungs by inhalation.

As used herein, the term “inhalation” refers to intake of air to thealveoli of the lung. In specific examples, intake can occur byself-administration of a formulation of the invention while inhaling, orby administration via a respirator, e.g., to a patient on a respirator.The term “inhalation” used with respect to a formulation of theinvention is synonymous with “pulmonary administration.”

The phrase “pharmaceutically-acceptable carrier” as used herein means apharmaceutically-acceptable material, composition or vehicle, such as aliquid or solid filler, diluent, excipient, or solvent encapsulatingmaterial, involved in carrying or transporting the subject copolymerand/or composition from one organ, or portion of the body, to anotherorgan, or portion of the body. Each carrier must be “acceptable” in thesense of being compatible with the other ingredients of the formulationand not unduly injurious to the patient. Some examples of materialswhich can serve as pharmaceutically-acceptable carriers include: sugars,such as lactose, glucose and sucrose; starches, such as corn starch andpotato starch; cellulose, and its derivatives, such as sodiumcarboxymethyl cellulose, ethyl cellulose and cellulose acetate; powderedtragacanth; malt; gelatin; talc; excipients, such as cocoa butter andsuppository waxes; oils, such as peanut oil, cottonseed oil, saffloweroil, sesame oil, olive oil, corn oil and soybean oil; glycols, such aspropylene glycol; polyols, such as glycerin, sorbitol, mannitol andpolyethylene glycol; esters, such as ethyl oleate and ethyl laurate;agar; buffering agents, such as magnesium hydroxide and aluminumhydroxide; alginic acid; pyrogen-free water; isotonic saline; Ringer'ssolution; ethyl alcohol; pH buffered solutions; polyesters,polycarbonates and/or polyanhydrides; and other non-toxic compatiblesubstances employed in pharmaceutical formulations.

The copolymer may be used in a therapeutically-effective (or“pharmaceutically-effective or active”) amount to provide treatment. Theamount will depend on the mode of administration such as oral,intramuscular, intravenous, inhalation or transdermal administration.The phrase “therapeutically-effective amount” as used herein means thatamount of a copolymer and/or a composition, material, or compositioncomprising the copolymer composition which is effective for producingsome desired anti-viral therapeutic effect.

The term acrolein-derived segment refers to the copolymer segmentcomprising one or more acrolein monomer residues.

The terms oligomer, polyalkylene glycol oligomer and polyacroleinoligomer refer to polymers consisting of at least two monomer units,preferably at least three monomer units. The oligomers will typicallycomprise from 2 to 20 monomer units; in one embodiment the number ofunits is from 2 to 10.

The terms “monomer units” and “monomer residues” refer to units presentin the copolymer derived from the reacting monomers such as acrolein andpolyalkylene glycol.

The polydispersity index is the ratio of the weight-average molecularweight (M_(w)) of the polymer to the number-average molecular weight(M_(n)) of the polymer. The weight-average molecular weight and thenumber-average molecular weight of a polymer can be determined byanalytical methods, such as high performance liquid chromatography. Oncethe weight-average and number-average molecular weights have beendetermined, the polydispersity index is easily calculated by dividingthe weight-average molecular weight by the number average molecularweight, M_(w)/M_(n). A hypothetically monodisperse polymer has apolydispersity index of 1.000. However, typical commercial polymers,such as the commercially available resins, have a polydispersity indexof 10 or more. Polymers with broad molecular weight distributions havehigher polydispersity indices and polymers with narrow molecular weightdistributions have lower polydispersity indices.

Throughout this specification, use of the terms “comprises” or“comprising” or grammatical variations thereon shall be taken to specifythe presence of stated features, integers, steps or components but doesnot preclude the presence or addition of one or more other features,integers, steps, components or groups thereof not specificallymentioned.

BRIEF DESCRIPTION OF DRAWINGS

Embodiments of the invention are described with reference to theDrawings. In the drawings:

FIG. 1 is a graph showing the CPA assay results of variation in %inhibition with concentration as described in Example 3.

FIG. 2 is a graph of the PRNT assay results of variation in % inhibitionwith concentration (%) of the formulation of Example 1 as set out inExample 3.

FIG. 3 is a graph showing the percent survival of mice infected withvirus in two groups: Group 1 treated with a copolymer of the inventionand Group 2 an infected control in accordance with Example 4.

DETAILED DESCRIPTION

The method of treatment comprises administering a copolymer comprisingsegment and a polyalkylene glycol oligomer segment (preferably ofmolecular weight of from 200 to 600 Daltons), the copolymer having amolecular weight of no more than 1500 Daltons, preferably no more than1000 Daltons.

The acrolein-derived segment may comprise one or more acrolein monomerresidues. In one embodiment the acrolein-derived segment comprises apolyacrolein oligomer.

The polyalkylene glycol may be a poly(C₁ to C₄ alkylene glycol) ormixture or copolymer thereof but in general the polyalkylene glycol ismost preferably a polyethylene glycol, preferably of molecular weight inthe range of from 200 to 600 Daltons.

It will be understood by those skilled in the art that the termpolyethylene glycol preferably does not include diethylene glycol.Polyethylene glycol of average molecular weight 200 to 600 Daltonsincludes polyethylene glycol of nominal average molecular weight 200 to600 Daltons wherein the average molecular weight is not more than 110%and not less than 90% (preferably not more than 105% and not less than95%) of the nominated value. Polyethylene glycol is of formulaH—[OCH₂CH₂]_(n)—OH. The average value of n is at least 3 and isgenerally from 3 to 13 (although the average need not be an integer).Polyethylene glycol is widely available from commercial suppliers inpharmaceutical grades and is sold in specified nominal molecular weightswhich generally signify that the average molecular weight is not morethan 105% and not less than 95% of the nominated value. The viscositiesand methods for molecular weight determination are disclosed in USP NFOfficial Compendium of Standards Volume 11180-1182 [2007 Edition]. Inone set of embodiments the polyethylene glycol is of molecular weightfrom 200 to 400. In some embodiments it may be preferred to use aspecific pure oligomer of ethylene glycol such as the compound offormula H—[OCH₂CH₂]_(n)—OH where n is 3 or 4.

In one set of embodiments the molecular weight (always meaning herein,the number average molecular weight) of the copolymer is at least 300Daltons preferably at least 400 Daltons such as in the range of from 400to 1500 Daltons and more preferably the molecular weight is in the rangeof from 400 to 1000 Daltons.

The treatment may be prophylactic or curative.

In another embodiment the copolymer is administered systemically, forexample, by oral administration, inhalation, transdermal delivery or byinjection such as into the blood stream or intramuscular injection or byintravenous therapy such as by injection or infusion. It is generallyaccepted that molecules of molecular weight no more than about 1000,particularly less than about 800 Daltons have reasonably free passageacross the abdominal membranes. Oral administration requires that thecopolymer is absorbed through the gut wall and into the systemiccirculation. In this embodiment it is particularly preferred that thecopolymer administered orally is of molecular weight no more than 1000Daltons such as a molecular weight in the range of from 400 to 800Daltons. We have found that copolymers of this molecular weight, whenadministered orally, are transported into the systemic circulation toprovide treatment of parenteral viral infection. The proportion of thecopolymer absorbed through the gut wall is generally greater forcopolymers of lower molecular weight in this range.

The copolymer may be applied as an aerosol, gel, topical foam orointment or impregnated into a dressing for application to skin ormucous membranes for transdermal or transmucosal delivery. The copolymermay be applied as an inhalation via an aerosol or the like.

In a further embodiment the copolymer is administered by transdermaldelivery from a composition which may comprise a penetration enhancerfor the polymer. Patches, micro-needles or like devices may be used toenhance transdermal delivery.

The compositions of the present invention may also contain adjuvantssuch as preservatives, wetting agents, emulsifying agents, anddispersing agents. Prevention of the action of microorganisms may beensured by the inclusion of various antibacterial and antifungal agents,for example, paraben, chlorobutanol, phenol, sorbic acid, and the like.It may also be desirable to include agents to adjust tonicity such assugars, sodium chloride, and the like. Prolonged absorption of theinjectable pharmaceutical form may be brought about by the inclusion ofagents which delay absorption such as aluminum monostearate and gelatin.

In another preferred embodiment, the pharmaceutical composition is in aform suitable for sub-cutaneous (s.c.) administration.

Pharmaceutical dosage forms suitable for oral administration includetablets (coated or uncoated), capsules (hard or soft shell), caplets,pills, lozenges, syrups, solutions, powders, granules, elixirs andsuspensions, sublingual tablets, wafers or patches such as buccalpatches.

The copolymer may be formulated in an aqueous composition as it issoluble and remains soluble over the full 1 to 14 range of pH. Thecopolymer may be administered in compositions with knownpharmaceutically-acceptable carriers and excipients; however aqueousformulations provide a significant advantage. The composition maycomprise a wide range of concentrations of the copolymer depending onthe specific virus to be treated and mode of administration. In one setof embodiments the concentration of the copolymer in an aqueouspharmaceutical composition is in the range of from 0.01% by weight to20% by weight of the composition. Accordingly, in a preferred set ofembodiments the copolymer is administered as an aqueous solution.

The composition may be administered orally in the form of a tablet,caplet, syrup or liquid and the dose administered orally will depend onthe severity and type of virus but may be in the range, for example, offrom 1 mg to 1000 mg per kilogram of bodyweight per day, such as from 10mg to 500 mg per kilogram of bodyweight per day.

The finding herein that acrolein-copolymers are active againstparenteral disease was not expected, due to the mechanism of actionbelieved to relate to their activity. U.S. Pat. No. 6,723,336 uses addedprotein to totally quench the antimicrobial activity ofacrolein-polymers. The focus of the prior art has been to treatinfections in the gastro-intestinal tract by oral administration ofacrolein-polymers having sufficiently high molecular-weights so as toprevent their trans-intestinal migration. Indeed the reactivity ofacrolein monomer is such that it has not heretofore been considered tobe feasible to polymerize acrolein so as to yield products havingmolecular weights no more than about 1,000 Daltons. Administrationagainst parenteral disease has also been deliberately avoided forreasons of their potential toxicity (including reaction with serumproteins).

In the prior art preparation of polyacrolein it was considered that themechanism of polymerization was anionic, and that water content neededto be minimized to avoid quenching of the anion or dissociation of theproduct. We have found that the molecular weight may be limited to 1000Daltons or lower by controlling the ratio of monomers, the dilution ofacrolein and polyethylene glycol with water and compared to prior art,keeping the pH in a lower range—maintaining the pH at no more than 12.0and preferably within a pH range of 12.0 to 7.0. That is, to achieve thenew mechanism of polymerization, the pH range is dropped two whole pHunits, or 100-fold lower hydroxyl-ion concentration than ever used inprior art polymerizations.

In one set of embodiments the invention provides a method forpreparation of a copolymer for treatment of a parenteral viral diseasethe process comprising base catalyzed polymerization of acrolein in anaqueous solution comprising polyethylene glycol (preferably of molecularweight of from 200 to 600 Daltons) wherein the ratio of polyalkyleneglycol/acrolein is at least 4, preferably at least 8, more preferably atleast 10, and water is present in an amount of at least 20% by weight ofthe composition.

In a preferred set of embodiments the process comprises adding anaqueous solution of acrolein, preferably having an acroleinconcentration of no more than 50% w/w, to an aqueous solution ofpolyethylene glycol comprising at least 10% w/w water and having a pH ofno more than 12.0, preferably no more than pH 11.

In a still more preferred embodiment acrolein is added as an aqueoussolution to an aqueous solution of polyalkylene glycol of pH 9 to 11.

In general we have found that in the aqueous systems used in theprocess, a relatively low pH such as no more than 12.0 such as not morethan 11.5 (preferably no more than 11) provides significant advantagesover the prior art pH range up to pH 14 used to polymerize acrolein.Relatively high pH, as used in the prior art for extended periods,provides oxidation and introduces carboxyl groups which improvesolubility. In contrast we have found that solubility is provided in theprocess of the invention without the need for extended heating atrelatively high pH and as a result the carbonyl and/or carboxyl contentis very low, typically 0-10% of the copolymer. The minimum carbonyl orcarboxyl content is believed to minimize both unwanted reaction withproteins of miscellaneous origins or repulsion to acidic and anioniccoatings of germs, thereby in both cases, enhancing antibiotic action.

Without wishing to be bound by theory it is believed that in the processof the present invention polymerization of acrolein in the presence ofalkali does not proceed by a totally anionic mechanism in the presenceof such significant amounts of water but rather has a significantfree-radical mechanism of polymerization.

This conclusion is supported by the facts that: (a) Polymerization wasfacilitated by the presence of the dual free-radical, oxygen (b) Waterwhich is a major component of the solvent, is anion-quenching (c)Polymerization is significant at ambient temperatures and above—fast,exothermic and inhibited by the typical free-radical inhibitor,hydroquinone—all observations being typical of free-radicalpolymerization, rather than ionic polymerization (Florey; Odian). Again,without wishing to be bound by theory, it is believed that the reactionmechanism involves formation of initiator-radical between oxygen andhydroxyl ion, followed by radical transfer to polyethylene glycolsolvent, thus initiating polymerization; then solvent-transfertermination involving solvent-hydroxyl to limit the number of acroleinresidues polymerized at the active radical site, adjacent to thecarbonyl within the copolymer.

The polyalkylene glycol oligomer is believed to provide chain-transferand/or chain-termination, thereby limiting, (together with the aqueousdilution), the molecular weight in direct proportion to the overallhydroxyl-content.

In overview, the core-strategy of the synthesis—and different from thatof the prior art U.S. Pat. No. 9,119,394, is to cause the two segmentsof the resulting co-polymeric product to be joined by a mechanism whichis believed, without wishing to be bound by theory, to proceed by afree-radical mechanism, rather than by a nucleophilic Michael addition.This is done by maximizing the formation of propagating free-radicalactive-centres (by maximizing the presence of the radical, oxygen)—andby minimizing pH, minimizing the formation of hydrogen-ion deficientactive-centres for nucleophilic Michael addition.

The active copolymer was shown by HPLC to have insignificant reactionwith either of the amino-acid models cysteine (sulfhydryl) or threonine(hydroxyl), and that the anti-disease activities of the copolymers canbe attributed to a non-covalent, physical hydrophobic effect alone, atthe identified proximate carbons within the copolymers, upon thestability of target cell membranes. The mechanism of action in the priorart, which relied on chemical reaction of carbonyl groups in modifiedpolyacrolein with protein, is not therefore believed to be responsiblefor the anti-virus activity of the present copolymers.

In contrast with the prior art which teaches the destructive reactivityof acrolein polymers with protein, we have found that the anti-virusactivity of the copolymer is not significantly depressed by the presenceof protein. We have found that the anti-virus activity of the copolymersare sufficiently fast so as to more than compete with any intra-vascularchemical reactions with protein leading to toxicity, or with in vivoclearing processes. In the perspectives of prior art, consistently,these observations and conclusion are counterintuitive to progressing tosynthesize and then use the copolymer (such as the copolymer ofExample 1) parenterally, as herein.

The copolymers disclosed herein represent a much-less toxicintra-vascular challenge than acrolein-polymers from prior art. We havefound that the copolymers may be prepared with a low polydispersity andthat a low polydispersity of preferably less than 5, more preferablyless than 2, and most preferably less than 1.5, still more preferablyless than 1.2, enhances the performance of the copolymer, particularlywhere the molecular weight is less than 1000, such as from 400 to 1000Daltons, more preferably 400 to 800 Daltons such as 400-600 Daltons. Thepolymers of the present invention may be prepared as a narrowsymmetrical and single polymer with polydispersity index ofapproximately 1. Previously described acrolein polymers generallycontain a higher polydispersity, or in the case of the polymer ofExample 6 of WO 09/059350, contain, on very sensitive UV detection,about 1% and about 8 times more of a wide range of lower molecularweight polymers/residues, which are not readily detectable fromrefractive index detection. The copolymers herein may be formedquantitatively, in narrow molecular weight distribution ofpolydispersity near unity. The copolymers contain much fewer potentiallytoxic contaminants (side-products and starting materials, includingresidual, lachrymatory acrolein) than heavily heated and autoxidizedacrolein-polymers of earlier art. In the preferred embodiment of theinvention, both carbonyl content and the pH used in preparation by basecatalyses are at an unprecedented minimum—and both factors may be usedto minimize side-products and their potential toxicity fromparticularly, Cannizarro reaction with carbonyl, and which prior art hasfound to be abnormally rapid in acrolein-polymers.

The copolymer has been found to have active anti-virus activity. Thisrepresents a new, general and successful method of treatment of viralinfection in a subject.

In addition to acrolein monomer, other monomers e.g., acrylic acid,acrylamide, acrylonitrile, vinyl chloride, styrene, methacrylic acid,methyl methacrylate, vinyl acetate, vinyl pyridine and vinyl pyrrolidonemay be used as additional monomers in preparation of copolymerscomprising a polyalkylene glycol oligomer segment and acrolein-derivedsegment, as described herein. The additional monomers may be present inamounts, which are not adverse to the anti-virus activity of thecopolymer. The ratio of monomers may be chosen so as to maintain thewater solubility of the copolymer and incorporation of other monomersmay be controlled by reaction conditions and relative monomerconcentrations bearing in mind monomer reactivity. In general it ispreferred that other monomers constitute no more than 15 mole % of themonomer residues of the copolymer, preferably no more than 10 mole % andmost preferable the copolymer only consists of polyalkylene glycol andacrolein monomer residues.

The hydrophobic mechanism, which is characteristic of the copolymers ofthe invention, is achieved through the process steps, which providecontrol over: molecular weight; affinity for anti-virus-reaction withvirions and cells infected with virus; enhanced anti-virus activity inthe presence of protein; and minimization of both carbonyl andcarboxyl-contents within the copolymers.

The copolymer anti-virus provided herein generally provide efficacyagainst a wide range of types of virus, whether resistant ornon-resistant to other chemotherapies.

In a preferred set of embodiments the method of preparation ofcopolymers of the present invention comprises the following steps:

providing a mildly basic (preferably of pH no more than 12.0; morepreferably of pH 9 to 11) aqueous solution of a polyalkylene glycol(preferably polyethylene glycol of molecular weight in the range of from200 to 600 Daltons);

stirring the mildly basic solution vigorously to entrain air; adding(preferably slowly over a period such as at least 2 minutes, morepreferably at least 5 minutes) acrolein as an aqueous solution ofconcentration no more than 50% w/w of the acrolein aqueous solution(usually containing preservative);

maintaining the reaction temperature in the range of from 10° C. to 40°C.; and once the acrolein monomer has been consumed, adding acid toprovide a pH less than 9 and preferably no more than 8.

The molecular weight of the resulting copolymer is controlled by themolecular weight of the polyalkylene glycol, as well as being directlyproportional to its hydroxyl concentration. (The polymerization beginsat ambient temperature, then rises slightly as the exothermicpolymerization—which is evident from the appearance and thendisappearance of yellow color from the preservative, progresses.)

During the reaction the stirring is preferably continued, and the pHmaintained mildly basic (preferably of pH no more than 12.0, morepreferably of pH 9 to 11), only as necessary. The addition of more baseand its concentration is minimized so as to lowerdegradation/side-reactions and to reduce carbonyl or carboxyl formationin the product.

Finally, the pH of the solution may be reduced. In a preferred set ofembodiments, the pH is adjusted to near neutral, by the addition ofacid. The extremely pungent smell of acrolein is no longer evident inthe copolymer product, which is generally formed in at least 99% yield.

The resulting acrolein-copolymers typically have molecular weights inthe range of from 250 to 1000 Daltons (such as 300 to 1000 Daltons, 400to 1000 Daltons or 400 to 800 Daltons). The copolymers are free ofturbidity which would be expected from any content of polyacrolein.Content of, and bonding between the acrolein-derived segment and thepolyethylene glycol oligomer segment, in the manner proposed earlier, isdemonstrated by the size separation-HPLC of all copolymers—each havingone-single, narrow, symmetrical, dominant and unresolvablemass-peak—without indicating either residual acrolein monomer orsubstantial polyacrolein; furthermore, the copolymer MW 1,000 fromExample 2, contrary to the resolvable change and expectation if theassociation between the segments was merely physicalinter-adsorption—did not change in size separation-HPLC, nor anti-virusactivity, after equilibration with polyethylene glycol MW 200 underbasic conditions comparable to those used in the original preparation ofall the copolymers. (See Example 2).

The weight-ratio of acrolein:polyethylene glycol used in its preparationof the copolymer is preferably between 1:4 and 1:40, and more preferablybetween 1:8 and 1:20.

The preferred base is an aqueous solution of an alkali hydroxide; morepreferably, the alkali hydroxide is sodium hydroxide.

The preferred acid is dilute hydrochloric acid—although acetic acid isuseful for pH buffering purposes.

It is preferred that the addition of acrolein to the aqueous solution ofpolyalkylene glycol takes about 10 minutes—and the reaction tocompletion, generally takes place about 40 minutes, and preferably is nomore than 90 minutes.

Typically we have found that a reaction time of 50 minutes is suitableto obtain virtually complete conversion to the copolymer product.

The acrolein is preferably added to the aqueous polyalkylene glycol asan aqueous solution—more preferably as a concentration in the range offrom 10% to 30% by weight of acrolein monomer, based on the weight ofthe aqueous acrolein solution to be added to the aqueous polyalkyleneglycol solution.

The resulting copolymer has a reactive carbonyl group-content (plus anycarboxyl-content) of less than 10%, more preferably less than 5%, andstill more preferably zero %.

The acrolein solution usually contains inhibitor, hydroquinone such asno more than 0.5% and typically 0.01 to 0.5% and more preferably 0.1%w/w.

It will be apparent to those in the art that the copolymers herein maybe included in a variety of compositions and physical forms.Particularly, compositions and pharmaceutical methods of use, in vivo,will be apparent, taking advantages of slower clearances of thecopolymer. Also, it will be apparent that pharmacological advantage maybe taken of variance in molecular weight to adjust the rate ofpenetration through membranes, tissues and organs—and the resultantabsorption or distribution within human or animal body; in this context,the lower molecular weight copolymers such as, for example 300 to 800Daltons are more rapidly absorbed and distributed than copolymers over amolecular weight of 1000 Daltons.

In view of the results herein, it is also conceivable to add protein,particularly broth to enhance in-use anti-virus activity of thecopolymers.

The subject products, herein, are aqueous-soluble and administration tohumans/animals may be by the usual methods known inmedicine—particularly, by mouth or injection—and are able to be used inany practical pharmaceutical way, alone or in compositions, withinorgans and tissues, or in contact with or in in vivo vascular systems ofeither humans or animals. When the copolymers are administered to humansand animals, they can be given per se or as a pharmaceutical compositioncontaining, for example, 0.1% to 99.5% (more preferably, 0.5% to 90%) ofactive ingredient in combination with a pharmaceutically-acceptablecarrier.

Compositions may be solids, solutions, gels, emulsions or suspensions ofmatter comprising a pharmacologically effective amount of the copolymer.The compounds of the invention can be used in combination with one ormore other chemotherapeutic agents. The dosage of the inventivecompounds may be adjusted for any drug-drug reaction. In one embodiment,the chemotherapeutic agent is selected from the group consisting ofmitotic inhibitors, alkylating agents, anti-metabolites, cell cycleinhibitors, enzymes, topoisomerase inhibitors such as CAMPTOSAR(irinotecan), biological response modifiers, anti-hormones,antiangiogenic agents such as MMP-2, MMP-9 and COX-2 inhibitors,anti-androgens, platinum coordination complexes (cisplatin, etc.),substituted ureas such as hydroxyurea; methylhydrazine derivatives,e.g., procarbazine; adrenocortical suppressants, e.g., mitotane,aminoglutethimide, hormone and hormone antagonists such as theadrenocorticosteriods (e.g., prednisone), progestins (e.g.,hydroxyprogesterone caproate), estrogens (e.g., diethylstilbesterol),antiestrogens such as tamoxifen, androgens, e.g., testosteronepropionate, and aromatase inhibitors, such as anastrozole, and AROMASIN(exemestane).

The copolymers and their compositions have substantial activity againstvirus.

Without wishing to be bound by theory, the mechanism of action providesadvantages:

-   -   that the copolymer described by this invention depends upon a        non-specific, hydrophobic reaction between the copolymer and the        proteins of the outer membranes of diseased cells—the reaction        will be greater, the greater the hydrophobicity of the outer        membranes of the cells and the metabolic activity weaken the        cells which increases internal osmotic pressure—greater than in        surrounding cells;    -   that the reaction weakens the membranes.

Therefore, the cells having greater internal metabolic activity willhave greater internal osmotic pressure, and greater outward pressureupon the outer membranes, giving comparatively greater sensitivity torupture from the effect of the copolymers.

This hypothesis has been put to testing and found successful.Furthermore it is general i.e., not specific and applicable to cellscontaining virus of all types.

It will be apparent to those in the Art that the metabolic activity,osmotic pressure and membrane-tension of cells containing virusespecially, will be greater than in surrounding cells—and the outermembranes will be more sensitive to the polymer described by thisinvention.

It is also known by those in the Art that bacterial infections may leadto cancer, due either to the infection causing chronic inflammation, orthe infection releasing cancer-inducing metabolites (Helicobacter pylorileading to cancer is a well-known example.). Thus, as the copolymerdescribed within this invention has already been found to be practicalas an antibiotic drug against bacteria, its virus and cancer activitiesas described here, should be advantaged and possibly synergistic. Also,as viral infection, particularly by influenza viruses is oftenassociated with bacterial infection as well—again, concurrent anti-viraland anti-biotic properties in the one drug are advantageouslysynergistic.

It will also be apparent that as Example 1 has the same or similarresultant extent of antibacterial activity against bacteria,irrespective of whether mutation has taken place to form asuperbug/resistant form of it—the same insensitivity to form occurs herei.e., the same propensity occurs irrespective of whether the virus is ina super (resistant) form, usually evolved through mutation.

It will also be apparent that other antibiotics (antibacterials),antiviral drugs than those described here may be considered for additionto formulations of the copolymers, so as to achieve added pharmaceuticaleffects.

The invention will now be described further with reference to thefollowing Examples. It is to be understood that the examples areprovided by way of illustration of the invention and that they are in noway limiting to the scope of the invention.

EXAMPLES

The copolymers from Example 1 and Comparative Example 1 have anti-viruscharacteristics. The lower MW 500 from Example 1—in vivo always—has beenfound to be more effective than higher molecular weight polymers ofacrolein and PEG.

Estimates of Carbonyl Content

The estimates of carbonyl content reported herein are based upon anestablished method (Peters 1962; Melrose 2009). In duplicate, an aqueoussample-solution of copolymer (1 g) was weighed to an accuracy of 0.01g—water (9 g) was added, and then the solution was brought to pH 6.00 bythe addition of either 0.01M hydrochloric acid or 0.01M aqueous sodiumhydroxide, as appropriate.

A 1% solution of hydroxylamine hydrochloride (50 mL) was brought to pH6.00 with 0.01M aqueous sodium hydroxide.

The above solutions of copolymer and reagent were mixed, and stood atroom-temperature for 30 minutes; the reactants were then back-titratedwith 0.01M aqueous sodium hydroxide (V mL) to pH 6.00.

Thus, the w/w % carbonyl-content of the original sample-solution (W g)was estimated as acrolein, equals: V×0.10×5.6/W.

Quantitative Analysis of Copolymer by HPLC

High Performance Liquid Chromatography (HPLC) was performed on ShimadzuProminence equipment using simultaneously, both refractive-index and UV(268 nm) detectors; the column was either or both (in series) WatersHydrogel 120 or Waters Hydrogel 250, for separation by size-exclusion.

MW calibration was done by a straight-line plot of exclusion-time versuslog MW of Sigma-Aldrich polyethylene glycols of average MW range 200 to10,000 Daltons. Thus, it follows from the method of determination thatthe molecular weights of acrolein-copolymers which were alwaysdetermined on this basis and reported herein—always refer to a NumberAverage Molecular Weight (corrected to the nearest 500 Daltons).

Separations were performed on aqueous solutions of solute (0.020 mL;0.4% w/w), with water-solvent (0.6 mL to 1.0 mL/minute).

Quantitative Analysis of Copolymer by Mass Spectrometry

Two separate techniques (by courtesy of Shimadzu Scientific Instruments(Oceania) Pty Ltd) were performed:

-   -   Direct injection into the mass spectrometer, without prior        chromatography;    -   Mass spectrometry, after prior chromatography

Equipment; experimental conditions were: Nexera UHPLC Binary HighPressure Gradient, and LCMS-8060 (run under Q3 scans to simulate singlequadrupole mass spectrometry; mobile phase equal parts 0.02% formic acidin water, and 0.02% formic acid in acetonitrile, and column PhemonenexAeris XB C18 300A 150×2.1 mm.

Quantitative UV/Visible Analysis of Polymer Solutions

Solutions for analysis were prepared by dilution of copolymer (250 mg)in water (20 g) and then if applicable, a stoichiometric molarequivalent of reactant; then, diluted 1:9 with water before taking theUV spectrum on Shimadzu UVmini-1240 equipment.

Example 1 and Comparative Example 1

Example 1 describes preparation of a copolymer of the invention ofmolecular weight of about 500 Daltons, comprising a polyacroleinoligomer segment, and a polyethylene glycol oligomer segment ofmolecular weight 200 Daltons. The copolymer is purposefully illustratedfrom a preparation at pH 12.0, as this is the highest pH recommended forreliable success, without introducing levels of unwanted side-reactionsas described herein. The anti-virus activity of the copolymer aregenerally higher compared with that of a corresponding copolymer ofmolecular weight approximately 2500 Daltons.

Example 1—Preparation of Copolymer of MW about 500 Daltons

A solution of freshly distilled acrolein (5 g; inhibited withhydroquinone 0.1% w/w) in water (20 g) was slowly added over 10 minutesto a solution of water (20 g) and polyethylene glycol (60 g; MW 200)which had been rendered pH 12 by the addition of 1M aqueous sodiumhydroxide; during the 10 minutes, the yellow color of oxidizedhydroquinone quickly appeared, then disappeared. During the process thecomposition was continuously and vigorously stirred to provide copiouscontact with air. An exothermic and rapid polymerization took-place, andthe temperature of the reactants was maintained between approximately25° C. and 35° C.

After another 50 minutes, the clear solution was adjusted to pH 7.5 bythe addition of 1M aqueous hydrochloric acid; the product was a clear,almost colorless (very pale yellow) solution. All the tests done on thesample and the results herein, were done on a sample without anypurification and having been stored for 4 or 6 years at 7° C.; this istaken as indicative of the high purity and high stability of theproduct.

The UV-visible, 200-600 nM spectrum of the product only had substantialabsorption in the far edge of the 200-300 nM region. This is consistentwith negligible content of unsaturation conjugated with carbonyl andwhich may be associated with propensity for a Michael Reaction

HPLC indicated the polymerization-yield was 99-100% w/w, and anyresidual acrolein—monomer was less than 1 ppm w/w; MW was approximately500 Daltons. Mass spectrometry showed base a base-peak of 312, andindicating the copolymer comprised five oxyethylene (ex PEG) residuescovalently joined linearly to two 2-propanal (ex acrolein) residues.

When tested down to pH 1 (and up to pH 14), the copolymer remainedsoluble. The copolymer has approximately 0-10% w/w carbonyl-content orcarboxyl-content.

The single peak of the product in HPLC remained narrow and unresolvedwhether HPLC was done in water at 1 ml/minute, over Waters Hydrogel 120,Waters Hydrogel 250 singularly or in series of either, alternatesequence.

The same preparative results occurred when the polymerization wasconducted at either pH 8 or pH 10, and always with exactly the same invitro microbiological rate-results against E. coli, and same HPLCresults (except pH 8 gave a product having an amount of materialsindicative of dimers or oligomers of acrolein of total amount less than1% w/w; in vivo microbiological rate tests were the same for allproducts.

The preparation of Example 1 was independently repeated a number oftimes, at various pHs between 8 and 12, including separately pH 8, pH 10and pH 12 by another member of the applicants' laboratory, and gaveidentical polymerization results, HPLC and in vitro rate-test resultsagainst E. coli.

Comparative Example 1—Copolymer of Molecular Weight about 2500 Daltons

This Example describes preparation of a copolymer, not of the invention,of higher molecular weight, 2500 Daltons comprising a polyethyleneglycol segment of molecular weight 2000.

A solution of freshly distilled acrolein (5 g; inhibited withhydroquinone 0.1% w/w) in water (20 g) was slowly added over 10 minutesto a solution of water (30 g) and polyethylene glycol (20 g; MW 2,000)which had been rendered pH 11 by the addition of 1M aqueous sodiumhydroxide; during this period, the yellow color of oxidized hydroquinonequickly appeared, and then disappeared. The composition was vigorouslymechanically stirred prior to and during addition to provide copiouscontact with air. An exothermic and rapid polymerization took place,with the temperature maintained between 25° C. and 35° C.

After stirring during an additional 50 minutes, the clear solution wasadjusted to pH 7.5 by the addition of 1M aqueous hydrochloric acid; theproduct was a clear, almost colorless (very pale yellow) solution.

It is noteworthy that in common with all polyacrolein-products in priorart, agar-diffusion techniques of microbiological analysis are not usedherein, due to resistance by relatively high molecular weight productsto diffusion through agar.

All the tests done on the sample and their results recorded herein, weredone on a sample without any purification and having been stored for 4to 6 years at 7° C.; this is taken as indicative of the high purity andhigh stability of the product.

The UV-visible, 200-600 nM spectrum of the product only had substantialabsorption in the far edge of the 200-300 nM region.

HPLC indicated the polymerization-yield was 99 to 100% w/w, and anyresidual acrolein—monomer was less than 1 ppm w/w; MW was approximately2,500 Daltons. When tested down to pH 1 (and up to pH 14), the polymerremained soluble. The polymer has approximately 0-10% w/wcarbonyl-content.

The single peak of the product in HPLC remained narrow and unresolvedwhether HPLC was done in water at 1 ml/minute, over Waters Hydrogel 120,Waters Hydrogel 250 singularly or in series of either alternate,sequence.

Based upon the polymerization mechanism described herein, It may becalculated that equivalents of acrolein monomer added in thepolymerization (in relation to equivalents of polyethylene glycol) aregreater in the case of Comparative Example 1, than Example 1, andtherefore any propensity to form any insoluble polyacrolein is greaterin the former, but was not observed, even after standing at 7° C./6years. Stepwise acidification of a dilute solution of theacrolein-polymer to pH 2.5 with dilute hydrochloric acid—andback-titration with dilute sodium hydroxide solution demonstrated theabsence of carboxyl groups (pKa=4.5).

Both copolymers were still stable after four years at 8° C., and werestable to simulated pH conditions during residence time in the humanstomach.

All observations were made between pH 6.5 and 7.0—this was quitenaturally attained, and avoided the complications of possibleinteractions with a variety of added salts from different buffers.

Example 2

This example demonstrated preparation of a copolymer of the invention ofmolecular weight of about 1000 Daltons comprising a polyethylene glycololigomer segment of molecular weight 600 Daltons.

A solution of freshly distilled acrolein (5 g; inhibited withhydroquinone 0.1% w/w) in water (20 g) was slowly added over 10 minutesto a solution of water (20 g) and polyethylene glycol (60 g; MW 600)which had been rendered pH 10 by the addition of 1M aqueous sodiumhydroxide. The composition was vigorously stirred before and during theaddition of acrolein to entrain air and provide copious contact withair, an exothermic and rapid polymerization resulted and the temperaturewas maintained between about 25° C. and 35° C. After commencement of theaddition the yellow color of oxidized hydroquinone quickly appeared andthen disappeared resulting in a clear solution.

After another 50 minutes, the clear solution was adjusted to pH 7 to 8by the addition of 1M aqueous hydrochloric acid; the product was aclear, almost colorless (very pale yellow) solution. (The UV-visible,200-600 nM spectrum of the product only had substantial absorption inthe far edge of the 200-300 nM region.)

HPLC indicated the polymerization-yield was 99-100% w/w, and anyresidual monomer was less than 1 ppm w/w; MW was approximately 1,000Daltons. When tested down to pH 1 (and up to pH 14), the copolymerremained soluble. The polymer has approximately 0-10% w/wcarbonyl-content.

Polyethylene glycol MW 200 (120 mg) was added to the copolymer (383 mg),then one drop of 1M sodium hydroxide to bring the pH to 11; afterstanding at ambient temperature for 2 hours, the pH was adjusted to 7.5with a drop of 1M hydrochloric acid, and stood 3 days. Neither the HPLCnor the anti-virus activity of the copolymer changed as the result ofthis treatment.

Example 3

Part 1 In Vitro Anti-Viral Evaluations of Example 1 Against Influenza aTX/36/91 (H1N1) Firstly, in a CPE Assay (and Cytotoxicity of theAntibiotic), and Secondly, in a PRNT Study.

The following two examples of in vitro activities of Example 1 arerepresentative of instances when action is prophylactic/inside thecell—and action is curative/outside the cell, respectively.

CPE—Cytopathic Effect Assay—FIG. 1

-   -   MDCK cells were seeded in 96-well plates and incubated overnight    -   The next day cells were infected with IFV A/TX/36/91 at an MOI        of 0.01 for 24 h at 35° C.    -   The following day serial dilutions of Example 1 (starting at        0.1% (1000 ppm) with 2-fold dilutions) were prepared in medium    -   The inoculum was removed from the cells and the serial dilutions        were added to the cells for 1 h at 35° C.    -   Compound dilutions were removed and cells were evaluated for        viral antigens by ELISA.

Cytotoxicity Assay

-   -   MDCK cells were seeded in black-walled 96-well plates and        incubated overnight    -   The next day growth medium was removed from the cells and        incubation medium was added    -   The following day serial dilutions of Example 1 were prepared as        described for the CPE assay    -   The medium was aspirated from the cells and the compound        dilutions were added for 1 h at 35 C. Cells that were incubated        with medium only were used for 0% cytotoxicity data    -   Medium was aspirated and cells were lysed for evaluation of the        ATP content on day 5 using Promega's CelltiterGlo kit    -   The resulting luciferase luminescence was quantified and used to        calculate the CC50 using 4-PL curve fit.

PRNA—Plaque-Reduction Neutralization Assay (and Cytotoxicity of theAntibiotic)—FIG. 2

-   -   Vero cells were seeded in 24-well plates and incubated overnight    -   The next day serial dilutions of Example 1 (starting at 0.1%        (1000 ppm) with 2-fold dilutions) and the control antibody were        prepared in medium    -   The serial dilutions were incubated with 200 PFU of IFV        A/TX/36/91 for 2 h at 35° C.    -   Afterwards the inoculum was added to the cells for 1 h at 35° C.    -   The inoculum was removed and the plates were incubated for 5        days    -   Virus titers were determined by immunoplaque assay

Cytotoxicity Assay

-   -   Vero cells were seeded in black-walled 96-well plates and        incubated overnight    -   The next day serial dilutions of Example 1 were prepared as        described for the PRNT assay    -   The growth medium was aspirated from the cells and the compound        dilutions were added. Cells that were incubated with medium only        were used for 0% cytotoxicity data    -   Compound was removed after 1 h and fresh medium was added before        placing the plates at 35° C. for 5 days    -   Medium was aspirated and cells were lysed for evaluation of the        ATP content on day 5 using Promega's CelltiterGlo kit    -   The resulting luciferase luminescence was quantified and used to        calculate the CC50 using a 4-PL curve fit. The results are shown        in Table 1.

TABLE 1 DATA Formula 1 PRNT50 EC50 [%] % Inhib. SD % Inhib. SD 0.1 100.00.0 62.2 8.9 0.05 99.4 0.9 57.9 10.5 0.025 88.9 0.0 45.1 7.9 0.0125 68.614.8 51.2 1.1 0.00625 56.3 9.6 47.5 6.9 0.003125 31.1 12.2 42.2 2.00.001563 8.2 11.5 0.000781 7.7 7.0 0.000391 13.2 13.1 0.000195 0.0 0.0

No cytotoxicity was observed between copolymer described as Formula 1and either MDCK (canine) cells or Vero (monkey) cells.

Example 4—In Vivo Antiviral Evaluation

This example examines the in vivo activity of the copolymer of Example 1in control of viral infection, specifically influenza A TX/36/91 (H1N1).

A treated group of 10 mice “Group 1” were compared with an untreatedgroup of 10 mice to examine the response to viral infection.

Group 1 (intravenously infected by intra-nasal administration; treatedsubsequently at a dose-rate of 140 mg/kg of mouse during each of thefirst 5 days with Example 1 70 mg/kg). Group 2 (intravenously infectedby intra-nasal administration; not treated). After 4 days, mice werebeginning to show symptoms of the illness. Mice which did not survive,one died, the remainder were euthanized—either as the result of having(a) lost 20% body-weight or (b) lost mobility due to apparent sickness.

The survival rate is shown in Table 2.

TABLE 2 Day 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Group 100% 100% 100%100% 90% 40% 20% 20% 20% 20% 20% 20% 20% 20% 20% 20% 1 Group 100% 100%100% 100% 10% 10%  0%  0%  0%  0%  0%  0%  0%  0%  0%  0% 2

The results are presented in the graph shown in FIG. 3.

1.-30. (canceled)
 31. A method of treatment of a parenteral viralinfection in a subject comprising administering to the subject acopolymer comprising an acrolein-derived segment and a polyalkyleneglycol oligomer segment, the copolymer having a molecular weight of nomore than 1000 Daltons.
 32. The method according to claim 31, whereinthe acrolein-derived segment is a polyacrolein oligomer comprising twoor more acrolein residues.
 33. The method according to claim 31, whereinthe copolymer has a molecular weight of from 300 to 1000 Daltons. 34.The method according to claim 31, wherein the polyalkylene glycololigomer segment has a molecular weight in the range of from 200 to 600Daltons.
 35. The method according to claim 31, wherein the polyalkyleneglycol oligomer segment has a molecular weight in the range of from 200to 400 Daltons.
 36. The method according to claim 31, wherein apolyalkylene glycol of the polyalkylene glycol oligomer segment ispolyethylene glycol.
 37. The method according to claim 31, wherein thecopolymer has a molecular weight of from 400 to 800 Daltons.
 38. Themethod according to claim 31, wherein the copolymer is administeredsystemically.
 39. The method according to claim 31, wherein thecopolymer is administered by a route selected from the group consistingof oral administration, inhalation, transdermal delivery and injection.40. The method according to claim 31, wherein the copolymer isadministered by oral administration.
 41. The method according to claim31, wherein the copolymer is administered by intravenous injection orinfusion.
 42. The method according to claim 31, wherein the copolymer isadministered as an aqueous solution comprising a copolymer concentrationin the range of from 0.01% by weight to 20% by weight of the aqueoussolution.
 43. The method according to claim 31, wherein the copolymer isadministered orally in the form of a tablet, caplet, syrup or liquid.44. The method according to claim 31, wherein the copolymer isadministered systemically at a dose in the range of from 1 mg to 1000 mgper kilogram of bodyweight per day.
 45. The method according to claim31, wherein the parenteral viral infection is selected from the groupconsisting of a influenza viral infection, an HIV infection, a hepatitisviral infection, a Ross River viral infection, and a herpes viralinfection.
 46. The method according to claim 31, wherein the parenteralviral infection is an influenza viral infection.
 47. A process ofpreparing a copolymer comprising an acrolein-derived segment and apolyalkylene glycol oligomer comprising: adding a first aqueous solutioncomprising an acrolein having an acrolein concentration of no more than50% w/w by weight of the first aqueous solution to a second aqueoussolution comprising polyethylene glycol and at least 10% w/w water byweight of the second aqueous solution; thereby forming a third aqueoussolution; and polymerizing the acrolein under conditions of alkalinecatalysis at a pH no more than 12 in the third aqueous solution, andthereby forming a copolymer, wherein: the molecular weight of thepolyalkylene glycol is from 200 to 600 Daltons and the copolymer has amolecular weight of no more than 1000 Daltons; the second aqueoussolution has a pH of no more than 12.0; the third aqueous solutioncomprises at least 20% w/w water by weight of the third aqueoussolution; and the copolymer has a weight ratio of polyalkyleneglycol:acrolein of at least 4:1.
 48. The process according to claim 47,wherein the second aqueous solution has a pH of from 9 to
 11. 49. Theprocess according to claim 47, wherein: the second aqueous solution is amildly basic aqueous solution having a pH of no more than 12.0; thepolyalkylene glycol has a molecular weight in the range of from 200 to600 Daltons; the mildly basic solution is stirred vigorously to entrainair; the first aqueous solution is added over a period of at least 2minutes the polymerization temperature is maintained in the range offrom 10° C. to 40° C.; and acid is added to provide a pH less than 9once the acrolein has been consumed.
 50. A copolymer effective intreatment of parenteral viral infection in a subject by systemicadministration, the copolymer comprising an acrolein-derived segment anda polyalkylene glycol oligomer segment wherein: the copolymer has amolecular weight of no more than 1000 Daltons; and the polyalkyleneglycol oligomer segment has a molecular weight in the range of 200 to600 Daltons.